Several weight loss programs rely on measuring ketones, either in the blood or in the urine, to make sure the dieter is in a constant state of fat burning. Here’s how this works… and a few extra pearls on how ketones modulate excitotoxicity in the brain, too. (I know this should probably be two separate articles, but I just couldn’t resist.) 

Physiology 101

Your body’s preferred energy source is glucose (sugar). That’s why sugar tastes so good to us: it has a very high glycemic index, meaning the body can turn it into glucose quite rapidly. Carbohydrates also have a very high glycemic index: the more processed the carb, the higher the glycemic index becomes. (Ever wonder why white bread tastes so good? Or why sugar gives you a pick-me-up in the afternoon, however brief?)

But when glucose isn’t available, due to prolonged fasting, starvation, intense exercise that consumes all your stores, or during a low-carb diet (since again, glucose is produced from carbs), your body will instead break down its fat stores and turn them into ketones. Most cells in your body can use ketones for fuel as a glucose substitute—including your brain, since ketones readily cross the Blood Brain Barrier.

(Side note: if you’ve heard of diabetic ketoacidosis, ketones are the same chemical involved, but at a much higher concentration in that case. What happens there isn’t that glucose isn’t available—it’s just that diabetics can’t produce the insulin necessary for the body to use the glucose it has. So the body instead begins to break down massive amounts of fat in order to produce ketones, so that the brain can continue to function. The problem here is that ketones are acidic—too many of them overwhelms the blood buffering system and the blood pH drops. This is life-threatening, but it does not occur in non-insulin dependent diabetics.)

Ketone Measurement for Fat Burning

One effective approach for weight loss, especially if you’re already eating well and doing everything right, is to start to measure your ketones. Between 0.5–1.5 mmol/L is good, and will result in some fat burning, but not optimal. Optimal nutritional ketosis is about 1.5 – 3 mmol/L in the blood. Levels below that mean you’re not in a fat-burning state, and might explain your obstacle to weight loss.

You can measure ketones via urine test strips, but they’re far less accurate than blood measurements.

Here’s a well-reviewed, relatively cheap monitor for blood levels, and the ketone test strips to go with it.

What If You’re Not in Optimal Ketosis?

The beauty of measuring is that you can adjust your diet—and if you’re not in ketosis, guaranteed you’re getting more carbs than you think you are. Lower the carbs even further, and increase the good fats. Sneak in extra healthy oils like coconut and ghee, butter and avocado oil wherever you can.

Ketones for Neurological Support

Ketones, it turns out, may do more than just substitute for glucose in the brain: this study shows that they also serve as antioxidants which can cross the Blood Brain Barrier.

I wrote here last week about brain excitotoxicity from over-stimulated NMDA receptors; prolonged excitotoxicity in the brain can lead to epilepsy, Alzheimer’s Disease, Parkinson’s Disease, Multiple Sclerosis, and ALS. We know that antioxidant support helps to calm down the inflammatory response of excitotoxicity; ketosis apparently acts as this kind of antioxidant support. In fact, this study shows that not only do ketones help to dampen down excitotoxicity from excess glutamate release, but they also encourage release of glutamate’s opposite neurotransmitter, GABA. (Go read last week’s article if you’re not following me here.) Ketogenic diets have also been used successfully for epileptics since the 1920s, and this may be the reason why they work.

This study shows that ketones may help Alzheimer’s Disease not only because of their antioxidant potential, but also because they may block the entry of amyloid proteins (those associated with Alzheimer’s) into the neurons. This makes sense, as Alzheimer’s is now being called “Diabetes of the Brain”: meaning the brain becomes less efficient at utilizing energy from glucose, thus entering an energy-deficient state. If ketones bypass this problem, it certainly makes sense that a ketogenic diet may be of therapeutic benefit.

But is it? This study suggests that it is: 152 patients with Alzheimer’s disease received either a ketogenic diet or placebo. Those on the ketogenic diet experienced significant cognitive improvement.

The Disclaimers and the Upshot

While nutritional ketosis for relatively short periods of time is a good way to lose weight, there are concerns about long-term ketosis, such as development of gout, constipation, and kidney stones. This all depends on how high blood ketone levels are, though. According to NIH researcher and ketone expert Dr. Richard Veech, for Parkinson’s improvement, improvements can start as low as 0.3 mmol/L, while Alzheimer’s improvement requires 5 mmol/L.

Definitely a fascinating new area of research, and one I will be watching!